Why We're Still Obsessed With the Kennedys

At the same time, many of the Kennedy heirs have used their celebrity to help the environment, run for political office and help the mentally ill.

Author Nasaw argues that the Kennedy family's service to America has far outweighed the scandals.

"The family could have gone to live in Monte Carlo in a kind of splendid isolation," Nasaw said. "But they stood for something."

The Nov. 22, 1963, assassination, with its spin of conspiracy theories, is enough to keep the mythology alive.

"It's an astounding story, a frightening one, but also a great story that lasts," Nasaw said. "A man, shot down literally in his prime when we don't know what happened. And it's an unfinished story that doesn't have an ending."